The present invention relates generally to laser imaging control systems. In particular, the present invention is a film cartridge bar code scanner and controller for a digital laser imaging system.
Laser imaging systems are commonly used to produce photographic images from digital image input data generated by magnetic resonance (MR), computed tomography (CT) or other types of scanners. Systems of this type can include a continuous tone laser imager for exposing the image on photographic film, a film processor for developing the film, and an image management system (IMS) for coordinating the operation of the laser imager and film processor.
The image input data is typically a sequence of digital values representative of the scanned image. Image processing electronics within the IMS processes the input data to generate a sequence of digital exposure values, each of which is representative of one of a plurality of intensity levels (eg., a grey scale) at a discrete pixel location on the image. The image processing electronics scales and maps the range of scanned input data values to a range of exposure values which will produce a useful, continuous tone photographic image. This mapping operation is necessitated by the nonlinear relationship between the input data and its visual representation, and the nonlinear sensitometric response of the photographic film to different intensities of light. The image processing electronics typically includes a lookup table of stored data characterizing the input data to exposure value transfer function. The lookup table is accessed by the image processing electronics as a function of the input data values to determine associated exposure values.
X-ray and other types of medical imaging photographic film are packaged in optically opaque containers. The film is usually removed from these containers and loaded in an insertable cartridge under darkroom conditions. The cartridge is then loaded into the laser imager. This is an inconvenient and time consuming task.
Known laser imaging systems commercially available from the 3M Company of St. Paul, MN are configured to receive different types of film having a variety of sensitometric (light sensitivity) characteristics. Since the overall image input value to exposure value transfer function is dependent upon the film sensitometry, parameters of these imaging systems must be adjusted for the particular film being used. Contrast and density controls interfaced to the IMS are manually actuated by an operator to accommodate different types of film in the 3M laser imagers referred to above. These adjustments are made on a trial and error basis with test patterns, an inconvenient and inefficient procedure.
Commonly assigned U.S. Patent application Ser. No. 07/656,734, entitled "Opening and Closing Mechanism For a Laser Imager Film Cartridge", which was filed on even date herewith, discloses a resealable imaging film cartridge and an opening and closing mechanism for use therewith. The opening and closing mechanism enables resealable cartridges with different sizes and types of film to be conveniently loaded into and removed from the laser imager. Unfortunately, the setup procedures described above must be performed by the operator each time a cartridge of film with different characteristics is loaded into the imager. The convenience advantages associated with the resealable cartridge and associated opening and closing mechanism are thereby diminished.
It is evident that there is a continuing need for improved control systems for laser imaging systems. The control system should enable an operator to quickly and conveniently configure the imaging system for different types of film. Other controlled functions which enable more precise control over the imaging system without requiring greater operator attention are also desirable. To be commercially viable, the control system must be reliable and of an efficient design.